Reader Daniella tried to free up storage on her Mac after finding she only had 16GB available:
I decided to delete a lot of files in my MacBook Pro. I also emptied my Trash and restarted my laptop. However, when I checked my storage after deleting files, I saw that it didn’t increase my storage but it lessened to 14.87GB. How is that possible? What happened?
This is a multifaceted problem which I’ve written about in bits and pieces before. It could be a Spotlight indexing error. Spotlight produces the information that’s used in the > About This Mac > Storage display. You can delete and re-index your Mac.
Restarting a Mac should clear temporary caches that can grow during a continuous session (between restarts/shut downs). However, it’s possible that due to applications used and available memory, OS X or macOS will create larger caches at startup time to handle swapping active program memory to and from disk.
Now as to how to free up storage, if you’re running Sierra, it includes extensive help in optimizing storage, deleted unneeded files, and shifting data to iCloud. Check out our overview from last fall.
Whether in Sierra or earlier versions, you can create a Spotlight search (and store as a smart folder) that helps you figure out your largest files, and then decide whether you need to delete them.
Using the instructions in our smart folder tutorial, create a Spotlight search in the finder for files above some arbitrary size—I’d recommend starting with 1GB. Using this as a guide, you might find surprising things. For example, I have uncompressed audio files from podcasts I recorded years ago where I no longer need the original. I also have various over-the-air recorded TV programs that I’ve watched or have decided I’ll never watch that are chewing up gigabytes.
Another option is to find a disk-cleaner app that isn’t horrible. Many packages, some with unnecessary monthly charges, perform badly and some even delete files without your permission. Macworld reviewed MacPaw’s CleanMyMac 3 in 2015, and found it a good solution. It’s $40 direct from MacPaw, but also part of the Setapp $10-a-month bundle, which can be purchased a month at a time.
Ask Mac 911
We’ve compiled a list of the questions we get asked most frequently along with answers and links to columns: read our super FAQ to see if your question is covered. If not, we’re always looking for new problems to solve! Email yours to firstname.lastname@example.org including screen captures as appropriate. Mac 911 can’t reply to—nor publish an answer to—every question, and we don’t provide direct troubleshooting advice.